// Copyright 2009 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/regexp/regexp-stack.h"

#include "src/isolate.h"

#include "src/objects-inl.h" // weolar

namespace v8 {
namespace internal {

    RegExpStackScope::RegExpStackScope(Isolate* isolate)
        : regexp_stack_(isolate->regexp_stack())
    {
        // Initialize, if not already initialized.
        regexp_stack_->EnsureCapacity(0);
    }

    RegExpStackScope::~RegExpStackScope()
    {
        // Reset the buffer if it has grown.
        regexp_stack_->Reset();
    }

    RegExpStack::RegExpStack()
        : isolate_(nullptr)
    {
    }

    RegExpStack::~RegExpStack()
    {
        thread_local_.Free();
    }

    char* RegExpStack::ArchiveStack(char* to)
    {
        size_t size = sizeof(thread_local_);
        MemCopy(reinterpret_cast<void*>(to), &thread_local_, size);
        thread_local_ = ThreadLocal();
        return to + size;
    }

    char* RegExpStack::RestoreStack(char* from)
    {
        size_t size = sizeof(thread_local_);
        MemCopy(&thread_local_, reinterpret_cast<void*>(from), size);
        return from + size;
    }

    void RegExpStack::Reset()
    {
        if (thread_local_.memory_size_ > kMinimumStackSize) {
            DeleteArray(thread_local_.memory_);
            thread_local_ = ThreadLocal();
        }
    }

    void RegExpStack::ThreadLocal::Free()
    {
        if (memory_size_ > 0) {
            DeleteArray(memory_);
            Clear();
        }
    }

    Address RegExpStack::EnsureCapacity(size_t size)
    {
        if (size > kMaximumStackSize)
            return kNullAddress;
        if (size < kMinimumStackSize)
            size = kMinimumStackSize;
        if (thread_local_.memory_size_ < size) {
            byte* new_memory = NewArray<byte>(size);
            if (thread_local_.memory_size_ > 0) {
                // Copy original memory into top of new memory.
                MemCopy(new_memory + size - thread_local_.memory_size_,
                    thread_local_.memory_, thread_local_.memory_size_);
                DeleteArray(thread_local_.memory_);
            }
            thread_local_.memory_ = new_memory;
            thread_local_.memory_size_ = size;
            thread_local_.limit_ = reinterpret_cast<Address>(new_memory) + kStackLimitSlack * kSystemPointerSize;
        }
        return reinterpret_cast<Address>(thread_local_.memory_) + thread_local_.memory_size_;
    }

} // namespace internal
} // namespace v8
